The present invention relates to an apparatus for vaporizing a disinfectant by dropping it on a heating element. The apparatus is applied to such a technical field that, when a packing material including a container or the like is sterilized or disinfected by using disinfection gas, the material to be sterilized is sterilized by dropping a disinfection liquid on the heating element to vaporize the liquid, introducing the vaporized gas, with a heated carrier gas, to the surface of the material to be sterilized and condensing the carried disinfection gas on the surface of the material to be sterilized.
Heretofore, there is disclosed in the above-mentioned technical field a method using hydrogen peroxide as a disinfection gas and a spray vaporization method of the liquid. According to said spray vaporization method, it is necessary to provide a system for pressurizing hydrogen peroxide and a spray chamber. Some trouble in such a process, such as blinding of nozzles and hunting of spray, is likely to occur.
Therefore, the method of Japanese Patent Application 174235/86 has been proposed by the present applicant. The application adopts a drop vaporization method in which hydrogen peroxide is vaporized by dropping it on a board heating type or a falling heating type.
That is, according to the board heating type unit, a stainless net is provided on a heat transfer block as an evaporation surface, a blow-off opening for heated carrier air is provided above the evaporation surface parallel to the surface of the heat transfer block, the heated air is blown from the opening to promote the evaporation of hydrogen peroxide and the hydrogen peroxide gas is carried to the material to be sterilized. A filter means is provided adjacent to the outlet of the vaporization chamber so as to prevent droplet splashes of hydrogen peroxide caused by flow increase of the carrier air or by the spheroidal phenomenon of the liquid hydrogen peroxide on the heated surface from being carried with the hydrogen peroxide gas.
Referring now to the falling heating type unit, a stainless net is provided as a vaporization surface in a vertical double heat pipe, a blow-off opening for heated carrier air is provided below said double heat pipes and the heated air is blown up along the interval between the double heat pipes. Other features are substantially same as those of the board heating type unit previously explained.
In general, the drop vaporization method presents some difficulties in controlling the rate of supply of the material to be sterilized to the sterilizing apparatus and the drying conditions of the material to be sterilized. That is, if the droplet splashes of hydrogen peroxide are entrained with the hydrogen peroxide gas, the gas density becomes uneven, resulting in uneven sterilization of the surface to be sterilized. In order to overcome the above disadvantages, there should be provided a means for controlling the rate of supply of the material to be sterilized in accordance with the gas density or a means for controlling the drying temperature, the drying velocity or the like in the drying process of the material to be sterilized. With this, however, the control of the sterilization becomes complex.
The above disadvantages have not yet been overcome by the apparatus for vaporizing hydrogen peroxide liquid by dropping it on the heating unit, as disclosed in said Japanese Patent Application 17425/86. That is, according to said Japanese Patent Application 17425/86, because the board heating type unit thereof has a stainless net provided above the heat transfer block in the shape of the plate as the evaporation surface, the area to be heated extends horizontally and therefore uneven heating and thermo difference in some parts of the heated surfaces occur. With this, the gas density also becomes uneven and uniform supply of hydrogen peroxide as the disinfection cannot be conducted.
Further, the hydrogen peroxide which is not evaporized because of the uneven heating often accumulates at the bottom of the apparatus. Further, there also occurs large heating loss caused by the large heating area. Additionally, the prior filter means for preventing the drop splashes of hydrogen peroxide from accompanying the hydrogen peroxide gas is not sufficient to make the vaporized hydrogen peroxide gas uniform.
Further, according to the falling heating type disclosed in said Japanese Patent Application 174235/86, the heated surface is also large, and heat spreads vertically, and therefore it leaves the same disadvantages as those of the board heating type unit.